Immigration is a contentious issue across the country. But in Texas, which shares a 1,200-mile border with Mexico, it is something much more.

President Barack Obama‘s planned fundraising trip to the state became very political very quickly, amid the recent surge of children and families entering the U.S. illegally over the southern border. The White House decided against a trip to the border but added plans for a meeting with local leaders and Gov. Rick Perry. But even before the current crisis, immigration sat at the nexus of politics, economics and culture in the state — and looking at the spread of Texas’s foreign-born population helps explain why.

While any discussion of immigration invariably turns to the border (and there are large percentages of foreign-born people there), there are also big foreign-born populations in the state’s biggest cities and metro areas. In terms of raw numbers those counties hold the largest foreign-born populations in the state and they have a big influence.

Those places are Texas’s Democratic-voting bastions – around Dallas, Houston, Austin and San Antonio. In Houston, shown as Harris County on the map, 25% of the population, or more than 1 million residents, are foreign-born. That population, only 32% of which is made up of naturalized citizens and eligible to vote, is instrumental in making that county swing Democratic – President Obama won by less than 1,000 votes in 2012.

The influx of immigrants to those counties isn’t just a question of different people with different backgrounds coming to town. It is about people changing the politics of the place, and particularly the biggest places in the state. While this is true across the country (as we noted last week) the impacts are more direct and deeper in Texas.

Consider than even in Texas, which Republican presidential nominee Mitt Romney won by 16 percentage points in 2012, Mr. Obama won the vote coming out of 29 counties where the percentage of foreign-born residents is above the state average of 16.3%. And the president won that vote handily, 53% to 45%.

Furthermore, the inward migration into Texas is increasing its foreign-born population. Texas has seen a net inflow of about of more 610,000 people since 2000, according to the Census, and a third of that population has come from international migration – again that’s compared to the current statewide foreign-born number of 16.3%.

Those big urban counties have seen some of the largest foreign-born inflows. In Dallas County, the Census estimates that there has been a net inward migration of 35,000 people and 29,000 of them are from another country. Census estimates that Harris County has seen a net inward migration of 102,000 people and 62,000 are from another country.

Foreign and Domestic Migration into Texas’s Big Counties

County

2013 Pop

Net Migration since 2000

International Migration

Domestic Migration

Bexar (San Antonio)

1,817,610

54,541

10,774

43,767

Dallas (Dallas)

2,480,331

35,107

29,330

5,777

Harris (Houston)

4,093,165

102,605

62,599

40,006

Tarrant (Ft. Worth)

1,911,541

48,119

14,634

33,485

Travis (Austin)

1,120,954

59,351

13,636

45,715

Those five big urban counties also led the way in job growth for Texas over the past five years. Data from the Bureau of Labor Statistics shows those five counties added 348,000 jobs between December of 2008 and December of 2013. The entire state, 254 counties, added about 660,000 over that time, according to BLS.

In other words much of story of Texas’s growth – in terms of economics and raw population – is tied to its growing foreign-born population and it’s not just a border-area story. It’s about the big urban Democratic-leaning counties in the state.

What’s playing out in Texas is a more intense version of the national story on immigration, and that is one very big reason why the debate there in particular is so charged.

About Washington Wire

Washington Wire is one of the oldest standing features in American journalism. Since the Wire launched on Sept. 20, 1940, the Journal has offered readers an informal look at the capital. Now online, the Wire provides a succession of glimpses at what’s happening behind hot stories and warnings of what to watch for in the days ahead. The Wire is led by Reid J. Epstein, with contributions from the rest of the bureau. Washington Wire now also includes Think Tank, our home for outside analysis from policy and political thinkers.